The invention relates to a hair removing apparatus comprising two co-operating hair processing members, which can be moved with respect to each other in a direction of movement and include, respectively, a first and a second plate-shaped carrier extending substantially parallel to the direction of movement, said two carriers, viewed parallel to a Z direction extending substantially perpendicularly to the carriers, being positioned with respect to each other by means of at least one positioning member provided with a contact element which engages a side of the second carrier facing away from the first carrier.
The invention also relates to a method of manufacturing a hair removing apparatus in accordance with the invention.
A hair removing apparatus of the type mentioned in the opening paragraph is disclosed in Research Disclosure, no. 591, May 1998, publication no. 40974. The known hair removing apparatus is a hair trimmer, and the two co-operating hair processing members each comprise a plate-shaped carrier, an edge of which extending parallel to the direction of movement is provided with a plurality of spaced apart teeth whose flanks are embodied so as to be cutting edges. The carriers can be moved to and for with respect to each other in the direction of movement as a result of the fact that one of the carriers can be driven, by means of an electric motor, in the direction of movement with respect to the other carrier, which is fixed in position. The carriers, viewed in a direction parallel to the Z direction, are positioned with respect to each other by means of two C-shaped clamping members which, viewed in the direction of movement, are centrally arranged, one leg of each clamping member engaging the side of the second carrier facing away from the first carrier, and the other leg engaging the side of the first carrier facing away from the second carrier. The stiffness of the clamping members is comparatively high. In the manufacture of the hair trimmer, one of the legs of each clamping member is bent by means of a laser adjusting device in such a manner that a desired gap width is obtained between the two carriers.
A drawback of the known hair removing apparatus resides in that, at the desirable gap width, undesirable friction forces between the two carriers in the direction of movement are substantially unavoidable. Such friction forces develop as a result of unavoidable tolerances in the thickness of the carriers. As a result of such tolerances, the facing sides of the carriers are not flat. This causes tolerances in the width of the gap present between the carriers and even contact between the carriers at a number of locations, resulting in comparatively high friction forces. When the carriers are moved with respect to each other, the friction forces may even become so large locally that seizure of the known hair removing apparatus takes place. Said friction forces can be precluded by increasing the average gap width. However, this has the disadvantage that locally the gap width becomes too large, which adversely affects the operation of the hair removing apparatus.
It is an object of the invention to provide a hair removing apparatus of the type mentioned in the opening paragraph, wherein friction forces between the two plate-shaped carriers are limited as much as possible, while a gap width, which is as small and uniform as possible, is still present between the plate-shaped carriers.
To achieve this object, a hair-removing apparatus in accordance with the invention is characterized in that the two carriers, viewed in a direction parallel to the Z direction, are positioned with respect to each other by means of a plurality of positioning members which, viewed in a direction parallel to the direction of movement, are arranged so as to be spaced apart, at least one of the carriers having a comparatively low bending stiffness. The expression xe2x80x9ca comparatively low bending stiffnessxe2x80x9d is to be taken to mean that the relevant carrier has so low a bending stiffness that the side of the relevant carrier facing the other carrier assumes a shape as a result of bending of the relevant carrier which corresponds at least substantially to a shape of the side of the other carrier facing the relevant carrier. The relevant carrier assumes said shape as a result of the fact that the carriers are positioned with respect to each other by means of said plurality of spaced apart positioning members, i.e. At a plurality of locations. As the facing sides of the two carriers are of corresponding shape, the tolerance of the gap width present between the two carriers is comparatively small. As a result, when the two carriers move relatively to each other, local contact between the two carriers is precluded as much as possible, and a comparatively small, uniform gap width between the two carriers is possible without the development of undesirably large friction forces.
A particular embodiment of a hair-removing apparatus in accordance with the invention is characterized in that the positioning members each comprise a tongue, which is cut and bent from the first carrier and provided with the contact element near an end portion, and in that the second carrier, viewed in a direction parallel to the Z direction, is enclosed between the first carrier and the contact elements of the tongues, said tongues extending through at least one opening in the second carrier. As the positioning members are formed from the first carrier in said manner, the number of parts of the hair removing apparatus is limited substantially, so that the hair removing apparatus is of a very simple construction.
A further embodiment of a hair removing apparatus in accordance with the invention is characterized in that the positioning members each comprise a tongue which is cut and bent from a third plate-shaped carrier extending substantially parallel to the direction of movement, and which is provided with the contact element near an end portion, and in that the first and the second carrier, viewed parallel to the Z direction, are enclosed between the third carrier and the contact elements of the tongues, said tongues extending through openings in the first and the second carrier, while at least two of the three carriers have a comparatively low bending stiffness. The third carrier is secured, preferably in a fixed position, to a frame of the hair removing apparatus, so that, in operation, the tongues do not move with respect to the frame as would be the case if the tongues were formed from the first or the second carrier. Dependent upon the design of the hair removing apparatus, such movements may be undesirable. As the tongues are not formed from the first or the second carrier, the first and the second carrier do not have to be suitable for the provision of such tongues, so that the choice of the material and the geometry of the first and the second carrier are not limited.
A still further embodiment of a hair removing apparatus in accordance with the invention is characterized in that one of the carriers is provided with a flanged edge extending substantially perpendicularly with respect to the carriers. In this embodiment, a comparatively high bending stiffness of one of the carriers is provided in a comparatively simple manner, so that the assembly of the carriers has a comparatively high bending stiffness. The other carrier(s) have a comparatively low bending stiffness in this embodiment, so that, when subjected to bending, they assume the shape of the carrier having the comparatively high bending stiffness, a comparatively small, uniform gap width being present between the carriers as well as an acceptable level of friction.
A particular embodiment of a hair removing apparatus in accordance with the invention is characterized in that the tongues are C-shaped or S-shaped. In the manufacture of the hair removing apparatus, C-shaped or S-shaped tongues can be manufactured by means of comparatively simple bending tools, and they are effective and reliable positioning members.
A further embodiment of a hair removing apparatus in accordance with the invention is characterized in that the tongues extend substantially parallel, or substantially perpendicularly, to the direction of movement. If the tongues extend substantially parallel to the direction of movement, the tongues can be given a width, viewed in a direction parallel to a Y direction extending perpendicularly to the direction of movement and the Z direction, which corresponds to a width of the openings in the carrier(s), viewed in a direction parallel to the Y direction. In this manner, the carriers are positioned with respect to each other by means of the tongues also in a direction parallel to the Y direction, so that a simple construction of the hair removing apparatus is provided. If the tongues extend substantially perpendicularly to the direction of movement, a distance between the contact elements of the tongues and the openings is not influenced, in operation, by the mutual movements of the two carriers, so that the tongues may have a limited length.
Yet another embodiment of a hair removing apparatus in accordance with the invention is characterized in that the first and the second carrier, viewed in a direction parallel to a Y direction extending perpendicularly to the Z direction and the direction of movement, are positioned with respect to each other by means of at least two further tongues, which are cut and bent from the first carrier, and which extend substantially without clearance through further openings in the second carrier, viewed in a direction parallel to the Y direction. In this embodiment, the first and the second carriers are positioned with respect to each other in a constructionally simple and practical manner, by means of said further tongues and further openings, in a direction parallel to the Y direction and guided with respect to each other in a direction parallel to the direction of movement.
A particular embodiment of a hair removing apparatus in accordance with the invention is characterized in that the first and the second carrier, viewed in a direction parallel to a Y direction extending perpendicularly to the Z direction and the direction of movement, are positioned with respect to each other by means of at least two further tongues, which are cut and bent from the first carrier, and which extend substantially without clearance through further openings in the first and the second carrier, viewed in a direction parallel to the Y direction. Also in this embodiment, the first and the second carrier are positioned with respect to each other in a constructionally simple and practical manner, by means of said further tongues and further openings, in a direction parallel to the Y direction, and guided with respect to each other in a direction parallel to the direction of movement.
A further embodiment of a hair removing apparatus in accordance with the invention is characterized in that the two co-operating hair processing members comprise, respectively, a cutting member and a hair manipulator, the cutting member being provided with a cutting edge extending parallel to the direction of movement for cutting hairs growing from skin, and the hair manipulator, viewed in a displacement direction of the hair removing apparatus, being arranged in front of the cutting edge for causing a movement of the hairs and the cutting edge with respect to each other in a direction parallel to the cutting edge. In this further embodiment, the hair removing apparatus is a shaver of the type disclosed in EP-B-0 855 256, wherein the hair manipulator comprises, for example, a comb which is arranged parallel to the cutting edge and which comprises teeth extending substantially perpendicularly to the cutting edge. In operation, reciprocating movements of the cutting member and the hair manipulator with respect to each other are generated in a direction parallel to the cutting edge by means of an electric driving device of the shaver, as a result of which the hairs are moved back and forth with respect to the cutting edge during cutting. By virtue thereof, a cutting force necessary for cutting the hairs is limited substantially, so that the shaver combines a very good shaving performance with a very high shaving comfort. In this embodiment of the hair removing apparatus, the invention manifests itself in a particular manner in that the shaving performance, the shaving comfort and the safety of the shaver of the type mentioned above are improved substantially as a result of the comparatively small and uniform gap width and the comparatively low friction between the carriers of the cutting member and the hair manipulator.
A still further embodiment of a hair removing apparatus in accordance with the invention is characterized in that the cutting edge is provided on an edge of the first carrier extending parallel to the direction of movement, while the hair manipulator comprises a plurality of teeth provided at intervals with respect to each other on an edge of the second carrier extending parallel to the direction of movement. By virtue thereof, a constructionally very simple and practical structure of the hair removing apparatus with the cutting member and the hair manipulator is provided.
A particular embodiment of a hair removing apparatus in accordance with the invention, wherein one of the carriers is provided with a flanged edge extending substantially perpendicularly with respect to the carriers, is characterized in that the flanged edge is provided on the second carrier. This embodiment is particularly advantageous in an embodiment wherein the second carrier, which carries the hair manipulator, is driven by means of an electric driving device in a direction parallel to the direction of movement, and wherein the first carrier, which carries the cutting member, is arranged in a fixed position with respect to a frame of the hair removing apparatus. The reason for this being that the flanged edge can be coupled to the driving device in a constructionally simple and practical manner. In addition, a large degree of freedom is provided as regards the choice of the material and the geometry of the cutting member.
A method in accordance with the invention for the manufacture of a hair removing apparatus in accordance with the invention is characterized in that during a first phase the tongues are pre-bent into a predetermined shape, during a second phase the carriers are arranged together and the tongues are provided in the relevant openings, during a third phase the contact elements of the tongues are pressed against the second carrier under the influence of a predetermined pressure, and during a fourth phase the pressure is removed. In said third phase, the tongues are further deformed under the influence of said pressure, and pressed with their contact elements against the second carrier. In this operation, elastic pretension develops in the tongues. The removal of the pressure causes the tongues to spring back elastically. The spring-back distance of the tongues is equal to the gap that forms between the contact elements and the second carrier. The size of the gap is so small that the hair processing members can move with respect to each other substantially free of clearance without hairs entering the gap between the hair processing members. If a small contact pressure between the carriers is desired after all, the tongues are heated in an intermediate phase between the third phase and the fourth phase approximately up to their melting temperature and, viewed across their thickness, in a uniform manner, while the pressure is maintained, and subsequently, after the tongues have cooled at least partly, the pressure is removed. As the pressure is maintained, it is precluded that the tongues spring back under the influence of said pretension. Said pretension disappears as a result of the fact that the tongues are heated. The tongues are heated uniformly, viewed across their thickness, so that substantially no thermal deformation of the tongues takes place during cooling, as a result of which the tongues do not become detached from the second carrier during cooling. When the pressure is being removed in said fourth phase, the assembly of carriers slightly springs back, as a result of which a comparatively small contact force develops between the second carrier and the contact elements of the tongues, and clearance between the second carrier and the contact elements is precluded. The hair removing apparatus thus manufactured has an accurately defined, comparatively small and uniform gap width between the carriers. As the contact forces between the tongues and the second carrier are comparatively small after the manufacturing process, the friction between the carriers is comparatively small.
A particular embodiment of a method in accordance with the invention is characterized in that the tongues are heated by means of a laser beam whose focus is directed at a distance from the tongues. The tongues are rapidly heated by means of the laser beam, so that the manufacturing process of the hair removing apparatus is accelerated. Use can be made of simple means to direct the laser beam to the tongues. As the focus of the laser beam is directed at a distance from the tongues, it is achieved that the tongues, viewed across their thickness, are heated as uniformly as possible, so that undesirable thermal deformations of the tongues during cooling are precluded as much as possible.
A further embodiment of a method in accordance with the invention is characterized in that, between the tongues, an additional pressure is exerted on the second carrier during the third phase and the intermediate phase. As a result of the additional pressure, the assembly of carriers is compressed more strongly during the third and the intermediate phase, so that the assembly also springs back more strongly during the fourth phase, resulting in a larger contact force between the contact elements of the tongues and the second carrier. This further embodiment of the method offers advantages, particularly, if the hair removing apparatus is provided with three carriers, because in such a hair removing apparatus the additional pressure causes clearance between the carriers to be more effectively precluded.